Exploring the denaturations in cancer and non-cancer DNA molecules by optical absorption, thermal, and electric measurements: A case study

In this article, we carried out the temperature dependent UV-Visible (UV-Vis) spectroscopy, differential scanning calorimetry (DSC), and electrical studies for normal and cancerous (glioma) DNA samples of single patient. Based on this method, we were able to monitor the denaturation process and thermal stability in these molecules. From the temperature dependent optical absorption data, we calculated various optical parameters for these two types of samples. The optical band gap of these samples were also estimated and discussed as per the experimental conditions. The various optical parameters calculated indicate that mutated (tumor) DNA is less stable than the normal one. From the DSC data, clear melting peaks were observed for the tumor and normal samples. Also various thermodynamic parameters like change in enthalpy (ΔH), entropy (ΔS), and specific heat (Cp) were estimated. From the thermal study, it seems that the tumor DNA is less stable. Further from the electrical or current-voltage (I-V) characteristics data, the resistance for normal DNA decreases with temperature. But for tumor sample, it show anomalous behavior (like decreasing and then increasing trend) with temperature. For electrical transport, small polaron hopping could be the possible transport mechanism in the current sample. Here from these studies, the tumor sample seems more disordered, and structural fluctuations due to the speculated structure could be the best reason for this behavior. If such kind of molecular (at nano scale range) studied are done more vividly, then these calculated parameters of the molecule could be explored for further confirmation/diagnostics of the diseases in addition to clinical investigations.